Long‐term nitrogen loading alleviates phosphorus limitation in terrestrial ecosystems
2020
Chen, Ji | van Groenigen, Kees J. | Hungate, Bruce A. | Terrer, César | van Groenigen, Jan‐Willem | Maestre, Fernando T. | Ying, Samantha C. | Luo, Yiqi | Jørgensen, Uffe | Sinsabaugh, Robert L. | Olesen, Jørgen E. | Elsgaard, Lars
Increased human‐derived nitrogen (N) deposition to terrestrial ecosystems has resulted in widespread phosphorus (P) limitation of net primary productivity. However, it remains unclear if and how N‐induced P limitation varies over time. Soil extracellular phosphatases catalyze the hydrolysis of P from soil organic matter, an important adaptive mechanism for ecosystems to cope with N‐induced P limitation. Here we show, using a meta‐analysis of 140 studies and 668 observations worldwide, that N stimulation of soil phosphatase activity diminishes over time. Whereas short‐term N loading (≤5 years) significantly increased soil phosphatase activity by 28%, long‐term N loading had no significant effect. Nitrogen loading did not affect soil available P and total P content in either short‐ or long‐term studies. Together, these results suggest that N‐induced P limitation in ecosystems is alleviated in the long‐term through the initial stimulation of soil phosphatase activity, thereby securing P supply to support plant growth. Our results suggest that increases in terrestrial carbon uptake due to ongoing anthropogenic N loading may be greater than previously thought.
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